Meaning of a kiss can vary

Published: Monday, January 1, 2007 at 3:30 a.m.

Last Modified: Sunday, December 31, 2006 at 11:00 p.m.

“The decision to kiss for the first time is the most crucial in any love story," said the Polish author Emil Ludwig. But why do we kiss, and what does it really mean?

As with anything dealing with love, there is no quick answer, except to say that it depends.

First, you have to consider who you are kissing and why. There’s a difference in kissing your grandmother goodbye after a family reunion and kissing a romantic partner.

And as Jason DeCaro, assistant professor of anthropology at the University of Alabama, points out, what about the kiss on the cheek that is a customary greeting in some parts of Europe, even for strangers? Or Judas’ infamous kiss of betrayal?

“Kissing means getting close, expressing trust, allowing a certain vulnerability," DeCaro said. “Humans are caught between our amazing ability to trust and work together with each other, and our breathtaking capacity to do each other harm. As a very social species, we need mechanisms like kissing, ways to signal 'I’m with you.’ "

Just as the meaning of a kiss changes depending on who and why, so do the emotions we feel and what’s going on inside our brains and bodies, DeCaro said.

In the brain, trust and attachment are linked to the action of the neurotransmitter oxytocin. Oxytocin tamps down stress and anxiety, and helps you form and maintain strong bonds. The things oxytocin does in your brain have effects throughout the rest of the body, too. For example, you could experience reduced blood pressure, muscle relaxation, even reduced responsiveness to pain.

A kiss to a child or with a longtime spouse may bring feelings of comfort and a sense of attachment or bonding, while a lustful kiss is about sex drive and the hormone testosterone.

Helen Fisher, an anthropologist at Rutgers University, has made a distinction between three types of “love:" lust, attraction and attachment, each with its own brain chemistry and role in animal behavior, not just humans, as it turns out.

“But then there’s also the romantic kiss, the kiss of what Fisher has called 'attraction,’" DeCaro said. “This kind of kiss tells a different tale: an interest in forming a bond where it doesn’t yet firmly exist. It brings with it the excitement of a new relationship, which is different from the comfort of long term attachment."

There’s some evidence that dopamine, another neurotransmitter, is heavily involved in that kind of kiss. Dopamine is part of the pathway in the brain that generates feelings of desire. It can make you feel like you’re full of energy. But other chemicals are probably involved as well. A romantic kiss is exciting, and with that kind of excitement the catecholamines come into play: epinephrine, also known as adrenaline, and norepinephrine, which lead to increased heart rate and blood pressure, faster breathing, increased muscle tension and more, which are feel good but, as DeCaro points out, can’t last forever, because the body is not built to withstand that for long periods of time.

So it’s not just the physical act of kissing that brings on these responses in the body and the brain – it’s everything that goes along with the kiss to tell you what the kiss means.

So, were the first men and women sitting around bored one day and turned to each other and said, “Hey! Let’s press this part of our bodies to each other and see what happens?"

“No, probably not," DeCaro said. “It likely goes much deeper than that. Consider the lips have an enormously dense collection of nerve endings. Touching of the lips is a great way to send a really strong message to the brain. This is true even though the meaning of that message may be different depending on the circumstances.

“We’re also not the only animals that use our lips this way. For example, French kissing is part of the social glue that holds bonobo society together, sometimes called pygmy chimpanzees. Many other less closely related animals use touch as a way to communicate as well, and in some cases, this involves the mouth. In evolutionary time, touching of lips and mouths as a way to bond probably goes back well before we were humans."

But at the same time, that doesn’t mean passionate kissing is a human universal. Not all cultures put the same emphasis on kissing that we do – or, for that matter, on romantic love. There are other ways to get along with each other and send messages, too.

But if you had a great midnight kiss Sunday night, you might disagree with that.

<p>The decision to kiss for the first time is the most crucial in any love story," said the Polish author Emil Ludwig. But why do we kiss, and what does it really mean?</p><p>As with anything dealing with love, there is no quick answer, except to say that it depends.</p><p>First, you have to consider who you are kissing and why. There’s a difference in kissing your grandmother goodbye after a family reunion and kissing a romantic partner.</p><p>And as Jason DeCaro, assistant professor of anthropology at the University of Alabama, points out, what about the kiss on the cheek that is a customary greeting in some parts of Europe, even for strangers? Or Judas’ infamous kiss of betrayal?</p><p>Kissing means getting close, expressing trust, allowing a certain vulnerability," DeCaro said. Humans are caught between our amazing ability to trust and work together with each other, and our breathtaking capacity to do each other harm. As a very social species, we need mechanisms like kissing, ways to signal 'I’m with you.’ "</p><p>Just as the meaning of a kiss changes depending on who and why, so do the emotions we feel and what’s going on inside our brains and bodies, DeCaro said.</p><p>In the brain, trust and attachment are linked to the action of the neurotransmitter oxytocin. Oxytocin tamps down stress and anxiety, and helps you form and maintain strong bonds. The things oxytocin does in your brain have effects throughout the rest of the body, too. For example, you could experience reduced blood pressure, muscle relaxation, even reduced responsiveness to pain.</p><p>A kiss to a child or with a longtime spouse may bring feelings of comfort and a sense of attachment or bonding, while a lustful kiss is about sex drive and the hormone testosterone.</p><p>Helen Fisher, an anthropologist at Rutgers University, has made a distinction between three types of love:" lust, attraction and attachment, each with its own brain chemistry and role in animal behavior, not just humans, as it turns out.</p><p>But then there’s also the romantic kiss, the kiss of what Fisher has called 'attraction,’" DeCaro said. This kind of kiss tells a different tale: an interest in forming a bond where it doesn’t yet firmly exist. It brings with it the excitement of a new relationship, which is different from the comfort of long term attachment."</p><p>There’s some evidence that dopamine, another neurotransmitter, is heavily involved in that kind of kiss. Dopamine is part of the pathway in the brain that generates feelings of desire. It can make you feel like you’re full of energy. But other chemicals are probably involved as well. A romantic kiss is exciting, and with that kind of excitement the catecholamines come into play: epinephrine, also known as adrenaline, and norepinephrine, which lead to increased heart rate and blood pressure, faster breathing, increased muscle tension and more, which are feel good but, as DeCaro points out, can’t last forever, because the body is not built to withstand that for long periods of time.</p><p>So it’s not just the physical act of kissing that brings on these responses in the body and the brain – it’s everything that goes along with the kiss to tell you what the kiss means.</p><p>If you’ve ever heard someone say dramatically in some movie, 'The romance is gone, I feel nothing when we kiss...’ – well, it’s possible for that to happen, too," DeCaro said.</p><p>So, were the first men and women sitting around bored one day and turned to each other and said, Hey! Let’s press this part of our bodies to each other and see what happens?"</p><p>No, probably not," DeCaro said. It likely goes much deeper than that. Consider the lips have an enormously dense collection of nerve endings. Touching of the lips is a great way to send a really strong message to the brain. This is true even though the meaning of that message may be different depending on the circumstances.</p><p>We’re also not the only animals that use our lips this way. For example, French kissing is part of the social glue that holds bonobo society together, sometimes called pygmy chimpanzees. Many other less closely related animals use touch as a way to communicate as well, and in some cases, this involves the mouth. In evolutionary time, touching of lips and mouths as a way to bond probably goes back well before we were humans."</p><p>But at the same time, that doesn’t mean passionate kissing is a human universal. Not all cultures put the same emphasis on kissing that we do – or, for that matter, on romantic love. There are other ways to get along with each other and send messages, too.</p><p>But if you had a great midnight kiss Sunday night, you might disagree with that.</p>